1. Field of the Invention
The invention generally relates to a power supply circuit for an antenna, an antenna control system, and a digital communication device, and more particularly, to a power supply circuit in which the power switching of an antenna and an overload detection/notification function are realized by using a single pin, an antenna control system, and a digital communication device.
2. Description of Related Art
Antennas have been broadly applied in our daily life along with the development of communication technology. In order to allow an antenna to operate properly, a power supply circuit is usually disposed to supply electric power to the antenna. A power supply circuit for an antenna includes a power switch circuit and a protection circuit. The power switch circuit controls a power source to supply electric power to the antenna. The protection circuit cuts off the power supply to the antenna when the power supply circuit is overloaded, so as to protect related circuits from being damaged. However, such a power supply circuit does not come with any overload detection/notification function that can detect an overload and issue a detection signal for notifying a user when the power supply circuit is overloaded. Even though some power supply circuits come with the overload detection/notification function, at least two pins are required in such a power supply circuit. One of the pins is used for supplying electric power from the power source to the antenna, and the other pin is used for transmitting an overload detection signal to notify the user when an overload occurs.